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I'm looking at getting a kvm-over-ip setup for a server room. Typically these devices have 16 or so cat5 leads that come out of them and then a convertor that converts each cat5 into a vga & ps2 pair.

Can you run one cable from the unit into a switch, and then leads from the switch into each machine ? I have several machines on the other side of the server room that i'd like to have avaliable but i dont want to run 16 cables to them. I'm thinking this should be possible being IP layer and all, but as each device normally has its own cable out the back of the kvm unit i'm not certain.

Perhaps the kvm's rear ports act essentially like a switch anyway in which case it should work, or perhaps if i run all 16 cables into a seperate switch right next to it and aggregate the ports together, run one cable to a switch on the other side of the room with similar number of ports agregated together, then use that switch to plug each macine into ?

I'm fairly sure this is possible, but i just want to check before i shell out the cash as i've never tried it.

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up vote 4 down vote accepted

Nope you can use patch panels but not switches. The kvm does not use the cable as Ethernet. Rather a serial connection. Another interesting note. The farther you get from the unit the lower your resolution has to be.

This is true for avocent and mrv kvm units.

Speaking of saving cash look at your servers ipmi or ill capabiliTy. Most recent servers have something like this that will provide a software based kvm on the server itself.

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ill mark this one as correct as the resolution note is handy info. Lots of good answers here though. – Sirex Nov 23 '11 at 8:34

Depends on your KVM hardware. Some use real IP network, but majority only uses cat5 cabling without any IP traffic. Also some KVM hardware support hubs etc.

You can also put vga/ps2 capture device by the machines and access it over the IP, but often they don't work very well.

cat5 cabling consists 8 wires, four of which are used by ethernet. It would be a good guess your KVM harwdware only uses four pins, 1,2,3 and 6. Therefore you should be able to use get two connections via each cat5 cable if you just juggle the heads. And then it's possible to run one 64 -pin cable to the servers.

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In addition to KVM switches with integrated IP capabilities, you also could have a setup with a "classical" non-IP-enabled KVM and an IP redirection server appliance like this one serving the signals via IP.

But if you are going to purchase new hardware anyway, IP-integrated KVM solutions might be a better deal despite of costing slightly more. aside from VGA, Keyboard and mouse redirection they usually come with the ability to expose a virtual USB storage to the hosts - really handy if a machine is not booting and you need to "throw in" a rescue disk of some sort.

IPMI / iLO / DRAC remote management solutions are nice if you do not have a heterogeneous landscape, especially since they would offer services far beyond simple console redirection like USB redirection, power status information and control or a hard-reset service. But these solutions do have add-on licensing costs and often would require a separate switch port per machine to connect.

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